Sheet-heating furnace



(No Model.)

' E. J', FRANCIS 8v 0. B'ANFIELD.

SHEET HEATING FURNACE. No. 408.475. Patented Aug. 6, 1889.

I INVENTOR:

WITNESSES: W 5 V J ATTORNEYS.

N. Pains, Pholo-Lnnograpiwr, Wnhinglm 0.0.

ITED STATES ATENT Enron,

EvAN JAMES ERANcIs AND CHARLES BANFIELD, 0E LEECHBURG,

I PENNSYLVANIA.

SHEET-HEATING FURNACE.

SPECIFICATION forming part of Letters Patent No. 408,475, dated August6, 1889.

Application filed December 23, 1887- Serial No. 258,825. (No model.)

To all whom it may concern:

Be it known that we, EVAN JAMES FRAN- cIs and CHARLES BANEIELD, both ofLeechburg, in the county of Armstrong and State of Pennsylvania, haveinvented certain new and useful Improvements in Sheet-Heating Furnaces,of which the following is a full, clear, and exact description.

The object of the invention is to provide certain new and usefulimprovements in sheetheating furnaces by which the heat is permitted toheat the sheets to be annealed very uniformly.

The invention consists in a bottom for the heating-chambers ofsheet-heating furnaces formed of segregated masses, broken pieces orfragments of non-combustible material having interstitial passages, andpresenting a broken or uneven surface, as will be hereinafter fullydescribed and claimed.

Reference is to be had to the accompanyingdrawmg, forming a part of thisspecification,

in which the figure illustrates a sectional side elevation of asheet-heating furnace provided with our improvements.

In heating sheets in annealing or heating furnaces, it is necessary tohave a bottom made of some material that will allow the heat to passfreely under the sheets in order to heat them uniformly. The material atpresent employed is generally coke made from coal. This material isbroken up into small pieces and spread over the bottom of the furnace toa depth of about six inches, and presents a broken or uneven surface,which allows the heat to pass readily under the sheets, thus furnishinga very even heat. The coke, 011 account of the great heat in itself,causes the bottom of. the heating-chamber to become hotter than the restthereof, and consequently the bottom sheets will become too hot, therebycausing the sheets to be spoiled. Besides this, the coke soon burns awayand leaves a residue, which has to be removed frequently, and the bottomhas to be renewed. Unless extreme care is taken the residue unites withthe sulphur and adheres to the sheets, so as to cause them to becomemarked and spotted,

and frequently causes the several sheets to stick together, therebyspoiling said sheets, which have to be thrown away. The daily and almosthourly renewal of the bottom entails a great expense upon themanufacturer, besides causing a great amount of extra labor for theworkmen. WVith our improvement, presently to be described, thedifficulties above mentioned are overcome.

The sheet-heating furnace A, of any approved construction, is providedwith a fireplace B, connected with the space 0, in which the sheets tobe heated for the rolling-mill are placed in any suitable manner. Thespace 0 connects with the chimney D, and the bottom of the said space 0is formed by a non-combustible material F, placed on the bottom plate E,preferably made of metal and having its supports in the sides and theend of the furnace A and in the bridge-wall G. At the front end of thefurnace A is formed an opening H for the introduction of the sheets tobe heated into the space 0, and which also serves for the renewal of thebottom F whenever necessary. v

The non-combustible material F, forming the bottom of the space 0, maybe broken pieces or fragments of cinder or slag, or oxide of iron, orthe said material may be asbestus, soapstone, &c. The non combustiblesubstances described furnish a clean and remarkably cheap and durablebottom, and, as the said substances will not burn away, their durabilityis unlimited. A bottom made of such substances does not get hotter thanthe rest of the furnace, and consequently the bottom sheets to beheated, which are held in the space 0, are heated to the same degree asthe top sheets. The segregated character of these pieces or fragmentscauses interstitial passages to be formed, through which the heatedgases are free to pass, and the upper side of the bed presents a brokenor uneven surface. The pile of sheets therefore will, as above stated,be heated to the same degree at the bottom as at the top. The bottomdoes not furnish any dust, ashes, or sulphur, and hence the sheets to beheated or annealed are not marked or spotted and do not stick together.terstitial passages, and presenting a broken A bottom made, asdescribed, will last a long or uneven surface, substantially as setforth. time, thus saving a great expense to the manufacturer and laborfor the workman. EVAN J AhlfES FRANCIS. 5 Havin thus described ourinvention, What We elaim as new, and desire to secure by Let- CHARLESters Patent, is

A bottom for heating furnaces formed of Vitnesses: segregated masses,broken pieces or frag- J AS. A. LONG, IO ments of non-combustiblematerial havingin- J. JENKINS.

